
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>用循环将三个DIV变成红色</title>
<style>
#outer{width:330px;height:100px;margin:10px auto;}
#outer div{float:left;width:100px;height:100px;margin:0 5px;background:black;}
</style>
<script>
window.onload = function ()
{
	var oDiv = document.getElementById("outer").getElementsByTagName("div");
	var oBtn = document.getElementsByTagName("button")[0];
	oBtn.onclick = function ()
	{
		for(var i = 0; i < oDiv.length; i++) oDiv[i].style.background = "red";
	}	
}
</script>
</head>
<body>
<center><button>点击将DIV变成红色</button></center>
<div id="outer">
    <div></div>
    <div></div>
    <div></div>
</div>
</body>
</html>
